Constructing a Mongo DBObject from single-quote JS object with escaped characters?

Question

This question relates to the Java API / Driver, but may also be relevant to interfacing Mongo in other languages. I am new to Mongo and making some assumptions, so please correct me if I'm mistaken. A lot of documentation I'm finding, and references describe creating a DBObject given a structure like this:

{
    foo: "bar",
    baz: {
        x : { lorem: "Ipsum" },
        y: { dolor : "sit amet" }
    }
}

Assume the above object exists (unchanged) in a file called foo.json. Now, as I understand it, the content above is a JavaScript object literal (not valid JSON). Right? However, this is the form referenced as "JSON" in the Mongo documentation.

In any case, in my tests, I'm reading the foo.json file into a String and parsing it using (I believe) a fairly standard convention:

String fooString = readFile("foo.json");
Object o = com.mongodb.util.JSON.parse(fooString);
DBObject dbObj = (DBObject) o;

This works just fine. Now, since foo.json isn't valid JSON, I assumed I'd be able to use a similar JavaScript object form:

{
    foo: 'bar',
    baz: {
        x : { lorem: 'Ipsum' },
        y: { dolor : 'sit amet' }
    }
}

Ok, fine, that seems to work. Although, oddly enough in Mongo shell it appears to be stored with double quotes. Since that works, I'm making another assumption that I'd be able to handle the JavaScript object form with escaped single quotes:

{
    foo: 'bar',
    baz: {
        x : { lorem: 'Ipsum.  Isn\'t working' },
        y: { dolor : 'sit amet' }
    }
}

However, when I try to parse this object (using com.mongodb.util.JSON.parse(fooString) ), a com.mongodb.util.JSONParseException is thrown. Shouldn't all 3 forms be supported?

Note: I'm using the org.mongodb:mongo-java-driver:mongo-java-driver:2.11.2 .

Thanks in advance for any/all help.

score 2 · Accepted Answer · answered Apr 29 '14 at 16:19

2

JSON.parse is not a full-blown JSON parser, and it doesn't support escaped characters like that. If you want to manipulate JSON and objects, you're better off using something like MongoJack which was designed to work that way from the beginning.

answered Apr 29 '14 at 16:19

Trisha

3,891
1
25
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Thanks, I appreciate the answer :) I looked into [MongoJack](https://github.com/devbliss/mongojack) briefly, it seems to have fairly wide usage. Are there any other JSON parsers you could recommend for my scenario? – blong Apr 30 '14 at 19:01
1

You could look at [GSON](https://code.google.com/p/google-gson/), it's pretty easy to get started with and also fairly widely used. Although you might find you have to provide [special instructions for serialising ObjectIds](http://stackoverflow.com/questions/23061611/converting-bson-type-objectid-to-json-storing-in-mongodb-java/23393169#23393169) – Trisha May 01 '14 at 08:15

score 0 · Answer 2 · answered Apr 30 '14 at 07:59

0

Strictly speaking in JSON all strings should be double quoted - see the json spec

So the valid json document version would be:

{
    "foo": "bar",
    "baz": {
        "x": { "lorem": "Ipsum" },
        "y": { "dolor" : "sit amet" }
    }
}

Most JSON parsers handle some level of broken(ish) json but if you stick to spec it should work fine.

answered Apr 30 '14 at 07:59

Ross

17,861
2
55
73

So, does `JSON.parse()` appropriately handle escaped special characters if I were to build my JSON object with double quotes this way? – blong May 01 '14 at 14:04

Constructing a Mongo DBObject from single-quote JS object with escaped characters?

2 Answers2